1. Field of the Invention
The present invention relates to an automotive air conditioning system, and more particularly to an automotive air conditioning system in which an outlet air temperature controlling accuracy is enhanced.
2. Background Art
In vehicles such as passenger cars, an air conditioning system is equipped in order to maintain a temperature environment within a passenger compartment in good condition irrespective of outside air temperature conditions. In the automotive air conditioning system, normally, several outlets are provided in a panel in front of driver and front passenger seats. According to the automotive air conditioning system, an outlet air temperature is controlled appropriately so as to become a target outlet air temperature in order to maintain the temperature inside the passenger compartment to a set optimum temperature. The control of the outlet air temperature is implemented by controlling the opening of an air mix door adapted to be freely opened and closed which is disposed between an evaporator and a heater core which are installed in an air conditioning duct in such a manner as to control a mixing ratio of a hot air (a hot side air) with a cold air (a non-hot side air). The air mix door, which is provided upstream of the heater core, has a function to divide air passing through the interior of the air conditioning duct into the hot-side air and the non-hot side air.
A technique described in a JP-A-56-82626, for example, is known as a technique for controlling with good accuracy the outlet air temperature at an outlet of an automotive air conditioning system to a target outlet air temperature. According to the technique described in JP-A-56-82626, a temperature sensor is provided at the outlet, so that an actual outlet air temperature detected by the temperature sensor is compared with a target outlet air temperature set on a control system, and the opening of the air mix door is controlled so that the actual outlet air temperature approaches the target outlet air temperature.